Process parameter influence on selected quality features in high-pressure die casting

INTRODUCTION The need for robust high quality processes is rising and therefore a detailed understanding of the processes interdependencies is gaining importance. In order to achieve such an understanding in general and in particular for the experimental die that will be described later on, an extensive experimental study has been performed. Not only will the results be used to show the interdependencies but also to verify and improve the results of the numerical optimization routine that is developed within the Cluster of Excellence [1]. The presented study is part of the experiments that will be the foundation for development, improvement and verification of this routine which shall later on result in automatically designed die features that are manufactured with generative manufacturing technologies such as Selective Laser Melting, if necessary. EXPERIMENTAL SETUP The presented research has been carried out on a Bühler H-630 SC high-pressure die casting machine with a locking force of 700 tons. The experiments were performed with an AlSi9Cu3Fe alloy since it is still one of the most used alloys in the highpressure die casting industry. A square plate with a side length of 160 mm has been chosen as cast part geometry. The average wall-thickness of the part is 4 mm but the wall thickness is decreasing from 6 down to 2 mm along the diagonal of the plate. Since the die is a twin-cavity die, two identical plates are casted within one cycle. A more detailed description of the modular die setup and the implemented measurement concept is given in [2]. The main focus of the experiments were the influence of process parameters on the thermal balance of the die on one hand and the process parameter influence on the cast part quality on the other. Within these context the overheating of the melt, the piston velocity during the filling phase, the die temperature and the intensification pressure are believed to be the most important [3-8]. With a full fractional design of experiments the number of experiments, each parameter combination including six and more casting cycles, would have been too high. Therefore the Taguchi approach was chosen in order to reduce the amount of casting experiments to a reasonable amount [9]. In addition a full fractional experimental design including the parameters die temperature and intensification has been used since these parameters are believed to be the most important factors. For Process parameter influence on selected quality features in high-pressure die casting